Very long-term optical variability of high-mass X-ray binaries in the Small Magellanic Cloud

Rajoelimanana, Andry; Charles, P. A.; Udalski, A.

doi:10.1111/j.1365-2966.2011.18243.x

Cited by 87 publications

(141 citation statements)

References 66 publications

Supporting

Mentioning

121

Contrasting

Order By: Relevance

“…The source is most likely identical to the Chandra source CXOU J010428.7−723134 (Rajoelimanana et al 2011a;Schmidtke et al 2013a), although the Chandra position is 2.8 away from that of the proposed counterpart (using the coordinates from Zaritsky et al 2002). The optical star shows a period of 37.15 days in OGLE and MACHO data (Rajoelimanana et al 2011a), which might indicate the orbital period, but could also be an alias of a 0.972 d period, which Schmidtke et al (2013a) interpreted as non-radial pulsations of a Be star. Rajoelimanana et al (2011a) also reported a period of 707 s found in the Chandra X-ray data.…”

Section: Sources Without Detected Pulsationsmentioning

confidence: 98%

“…A flux upper limit from one XMM-Newton observation with no detection of the source combined with the Swift flux yields a flux ratio of >900, clearly suggesting a BeXRB nature of the source. Analysing OGLE II and III data of AzV285, (Coe et al 2009) found a 36.79 d period, which was revised by Rajoelimanana et al (2011b) to 36.41±0.02 d; this is probably the binary period. XMMU J010429.4−723136 − Source number 3285 in the SMC catalogue of Sturm et al (2013c) was proposed by these authors as an HMXB candidate.…”

Section: Sources Without Detected Pulsationsmentioning

confidence: 99%

“…From the RXTE SMC monitoring Galache et al (2008) identified an outburst pattern with a period of 362.3 ± 4.1 d in X-rays. Rajoelimanana et al (2011b) analysed the OGLE III data, which revealed a significant peak at 171 ± 0.3 d in the power spectra, which is less than half the reported X-ray period. Galache et al (2008) already noted that the X-ray period is longer than would be expected given its spin period position in the Corbet diagram (Corbet 1984;Laycock et al 2005, see also Fig.…”

Section: Update On Individual Bexrb Pulsarsmentioning

confidence: 99%

“…Description Liu et al (2005) HMXB catalogue of the Magellanic Clouds Coe et al (2005) Optical properties of HMXBs in the SMC Shtykovskiy & Gilfanov (2005) HMXBs in archival XMM-Newton data McGowan et al (2008b) Chandra SMC Wing survey Galache et al (2008) RXTE observations of SMC pulsars McBride et al (2008) Optical spectroscopy of BeXRB pulsars in the SMC New BeXRBs from XMM-Newton observations in Antoniou et al (2009b Optical identification of Chandra sources Antoniou et al (2009a) Optical spectroscopy of BeXRBs in the SMC Laycock et al (2010) Catalogue of SMC sources from deep Chandra observations a Rajoelimanana et al (2011b) Long-term optical variability of HMXB pulsars in the SMC Sturm et al (2013c) XMM-Newton survey of the SMC Coe & Kirk (2015) BeXRB pulsars in the SMC Notes. (a) Includes detections down to two net counts.…”

Section: Referencementioning

confidence: 99%

See 3 more Smart Citations

High-mass X-ray binaries in the Small Magellanic Cloud

Haberl

Sturm

2016

A&A

157

176

View full text Add to dashboard Cite

Aims. The last comprehensive catalogue of high-mass X-ray binaries in the Small Magellanic Cloud (SMC) was published about ten years ago. Since then new such systems were discovered, mainly by X-ray observations with Chandra and XMM-Newton. For the majority of the proposed HMXBs in the SMC no X-ray pulsations were discovered as yet, and unless other properties of the X-ray source and/or the optical counterpart confirm their HMXB nature, they remain only candidate HMXBs. Methods. From a literature search we collected a catalogue of 148 confirmed and candidate HMXBs in the SMC and investigated their properties to shed light on their real nature. Based on the sample of well-established HMXBs (the pulsars), we investigated which observed properties are most appropriate for a reliable classification. We defined different levels of confidence for a genuine HMXB based on spectral and temporal characteristics of the X-ray sources and colour-magnitude diagrams from the optical to the infrared of their likely counterparts. We also took the uncertainty in the X-ray position into account. Results. We identify 27 objects that probably are misidentified because they lack an infrared excess of the proposed counterpart. They were mainly X-ray sources with a large positional uncertainty. This is supported by additional information obtained from more recent observations. Our catalogue comprises 121 relatively high-confidence HMXBs (the vast majority with Be companion stars). About half of the objects show X-ray pulsations, while for the rest no pulsations are known as yet. A comparison of the two subsamples suggests that long pulse periods in excess of a few 100 s are expected for the "non-pulsars", which are most likely undetected because of aperiodic variability on similar timescales and insufficiently long X-ray observations. The highest X-ray variability together with the lowest observed minimum fluxes for short-period pulsars indicate that in addition to the eccentricity of the orbit, its inclination against the plane of the Be star circum-stellar disc plays a major role in determining the outburst behaviour. Conclusions. The large population of HMXBs in the SMC, in particular Be X-ray binaries, provides the largest homogeneous sample of such systems for statistical population studies.

show abstract

Section: Sources Without Detected Pulsationsmentioning

confidence: 98%

Section: Sources Without Detected Pulsationsmentioning

confidence: 99%

Section: Update On Individual Bexrb Pulsarsmentioning

confidence: 99%

Section: Referencementioning

confidence: 99%

See 2 more Smart Citations

High-mass X-ray binaries in the Small Magellanic Cloud

Haberl

Sturm

2016

A&A

157

176

View full text Add to dashboard Cite

show abstract

“…We found a clear variation both in strength and shape of the Hα line profiles in our spectra which implies that the structure of the equatorial disk around the Be star is changing over the years. This must be associated with the formation and dissipation of the equatorial disc around the B star as discussed in [22,23,24]. The ratio between the peak of the violet (V) and red (R) component of the Hα profile is also changing during the observations, indicating that the Be equatorial disc is slightly distorted.…”

Section: Discussionmentioning

confidence: 99%

SALT observations of the Be/X-ray binary A0538-66

Rajoelimanana¹,

Meintjes²,

Charles³

et al. 2016

Proceedings of SALT Science Conference 2015 — PoS(SSC2015)

View full text Add to dashboard Cite

The Be X-ray transient, A0538-66, is the most extreme LMC/SMC member of this class, exhibiting optical (and sometimes X-ray) outbursts with a period of 16.6d. More remarkably, long-term (MACHO) optical photometry revealed a large amplitude (∼0.5mag) 421d activity cycle which appears to control the appearance of the recurrent orbital outbursts/flares, as they are only seen during the minimum of the 421d cycle. The nature of the physical link between these features is very poorly understood, but is likely related to properties of the Be star's equatorial disc. We will present our recent results on the long-term spectroscopic observations of this LMC BeX system using both broad-band (wide wavelength coverage) as well as high resolution optical spectra obtained from the Southern African Large Telescope (SALT). These observations enable us to probe both the evolution of the Be star envelope and the details of its interaction with the neutron star in its presumed highly eccentric (e ∼ 0.7) orbit. The high resolution spectra also allows us to derive its rotational velocity and spectral classification.

show abstract